I just want to collect what you have said in these posts into a single entry that explains how to use both Michael 4 for Genesis 2 Male and the M4 Skins Autoconverter from start to finish. To clarify, the M4 Skins Autoconverter does not convert the skins themselves to new uvs, it converts the skin presets (.cr2, .mc6, .dsa, etc.) to fit the current figure and ready to save as a .duf.
1. Load Genesis 2 Male. He will load with the default skin and have Base Male as his UVs.
2. If the M4 texture preset you want to use is already in .DUF format, you simply need to click the preset and it will apply the M4 skin to Genesis 2 Male. The .duf preset used may or may not apply the M4 uvs when clicked. If it does, then you are all set. If it does not, use the Set M4 UVs preset located in your Scripts folder (also located in Materials/Masculine/Michael 4 for Genesis 2 Male) or set the UVs manually by selecting the surfaces in the Surface Pane and apply Michael 4 from the UV dropdown list.
3. If the M4 texture preset you want to use is NOT in .DUF format (such as .pz2, .dsa, .ds, .mc6) it will not be directly applied to Genesis 2 Male. Clicking one of these presets will do nothing because they do not contain the correct placement information to change the surfaces with the M4 textures (same thing with Generation 5 textures that are not saved in .DUF such as Dave for M5 which has .dsa files)
4. Click the M4 Skins Autoconverter preset located in your Scripts folder (labeled New Surfaces for Old G2M). A window will pop up telling you to Select the MAT file you want to load to G2F (should say G2M). Navigate to the folder containing the .pz2, .mc6, or .dsa that you would like to apply to Genesis 2 Male. For M4 textures, these are usually in one of two places: /Runtime/Libraries/Pose or /Runtime/Libraries/Materials. For M5 textures, they can usually be found in /My Library/People/Genesis/Characters or /My Library/People/Genesis/Materials. You will only see the thumbnail icons in this window. This is to make it easy to see what you are trying to find. Double click on the .png thumbnail of your chosen texture.
5. Autoconverter will apply all the textures included in the chosen preset. In most cases, it will apply the M4 UVs, but if it does not, you can do so by following the steps at the end of #2 above.
6. The final step is to save the newly placed skin to .duf format so you may use it again in the future. You will need to save the presets to your DAZ folder, not in the /Runtime folder where the original files were saved. I have a folder called Converted for G2M that I save all my new conversions to.
7. If you do not own the M4 Skins Autoconverter, you can create these .duf files manually by loading Michael 4 or Genesis 1 into the scene, use your current .pz2, .mc6, etc. presets to apply the skin, then save as .duf. Then open Genesis 2 Male and apply the newly created .duf to him. Using the autoconverter makes it much simpler and more convenient than the manual method, so I do recommend it.
I hope this clears up any confusion about the difference between the two products and how to use them. Mods, please consider linking to this post when the question comes up again.